1. Field of the Invention
This invention relates to an electronic device and more particularly to the structure and assembly of an electronic digital wristwatch.
2. Description of the Prior Art
The electronic digital wristwatch is powered by a small size battery such as a silver oxide battery and includes at least frequency divider means for dividing the frequency of a constant frequency signal derived from an oscillator circuit utilizing a crystal oscillator, counter circuit means for counting the output signal of the frequency divider means, decoder circuit means for decoding the output signal of the counter circuit means, and driver means for driving digital display means for visually displaying the time therein by the output signal of the decoder circuit means.
In such a small-sized electronic timepiece, simplification of the assembly of the so-called module in which is assembled the circuit elements of the electronic timepiece has been one of the main problems. Another of the main problems lies in how the occupation space of a module, particularly the thickness of the module, can be reduced. This is mainly for the purpose of reducing the thickness of the wristwatch as thin as possible. Further, from the point of mass-productivity, the geometric shape of the module to be installed in the outer casing of a timepiece should be commonly adaptable to various designs of the outer casing. Particularly in digital type timepiece, the shape of the outer casing is not limited to the disk shape which has been the fundamental shape for the wristwatches of both the digital and the hands display types. Various novel shapes may be adopted for the outer casing. Therefore, the module or the assembly of the circuit boards to be loaded in the outer casing should be so designed to be adaptable to various conventional and novel designs of the outer casing. Further, the shape of the module should be so designed that various variations in the shape of the digital display and in the display characters of the digital timepiece will necessitate only minor changes in part of the blocks or the circuit boards of the module. Further, the module to be loaded in an outer casing should be divided into an appropriate group of blocks or circuit boards from the point of easy assembly. Inappropriate block division of the module will complicate the assembling steps and gives undesirable results with respect to the above-described problems. Since the main part of the electronic circuit in the blocks or the circuit boards constituting the module is formed of a semiconductor pellet or pellets manufactured by IC techniques, the structure of the blocks or the circuit boards of the module assembly should be so designed as to enhance the adaptation of semiconductor IC techniques. Namely, the wiring in the blocks or circuit boards to which the semiconductor pellet is to be loaded or mounted should be so designed as to enhance the applicability of the semiconductor IC techniques. Further, the module of a timepiece should be shock-proof.